--- otherwise known as KIT to FLEECE before NG and R
In many parts of the US, the [ɪ] sound, as in kit, shifts upwards in the mouth towards [i], as in fleece, when it comes before the sounds [ŋ], as in ring, and [ɚ], as in hear. This means that those last two words might sound more like reeeng and heeer.
If you're trying to do that for an accent, then awesome! If you're trying to avoid it because you make those sounds habitually, then here are a couple of tricks:
With the NG: Try to make the NG sound happen further back in the mouth. Often it's the [ŋ] happening further forward on the tongue that makes the vowel shift upward.
Similarly, with the R sound: Think of it being a more open vowel sound of [ɚ] - so it's happening in a more open, resonant space, rather than becoming a harder R sound of [ɹ] that may feel tighter, as this is the consonant version of this sound.